trusty (1) grass-mysql.1grass.gz

NAME

       grass-mysql - MySQL driver

       MySQL  driver  MySQL  driver  in  GRASS  MySQL  database  driver  in  GRASS enables GRASS to store vector
       attributes in MySQL server.

       Because vector attribute tables are created automatically when a new vector is written and  the  name  of
       the  table  is  the  same as the name of the vector it is good practice to create a new database for each
       GRASS mapset.

Creating a MySQL database

       A new database is created within MySQL:
       mysql> CREATE DATABASE mydb;
        See the MySQL manual for details.

Driver and database name

       GRASS modules require 2 parameters  to  connect  to  a  database.   Those  parameters  are  'driver'  and
       'database'.  For  MySQL  driver  the  parameter  'driver'  should be set to value 'mysql'.  The parameter
       'database' can be given in two formats:

                      Database name - in case of connection from localhost

                      String of comma separated list of kye=value options.  Supported options are:

                             dbname - database name

                             host - host name or IP address

                             port - server port number
       Examples of connection parameters:
         db.connect driver=mysql database=mytest
         db.connect driver=mysql database='dbname=mytest,host=test.grass.org'

Data types

       GRASS supports almost all MySQL data types with following limitations:

                      Binary columns (BINARY, VARBINARY, TINYBLOB,  MEDIUMBLOB,  BLOB,  LONGBLOB)  are  not  not
                     supported.  If a table with binary column(s) is used in GRASS a warning is printed and only
                     the supported columns are returned in query results.

                      Columns of type SET and ENUM are represented as string (VARCHAR).

                      Very large integers in columns of type BIGINT can be lost or corrupted because GRASS  does
                     not support 64 bin integeres on most platforms.

                      GRASS does not currently distinguish types TIMESTAMP and DATETIME. Both types are in GRASS
                     interpreted as TIMESTAMP.

Indexes

       GRASS modules automatically create index on key column of vector  attributes  table.  The  index  on  key
       column  is  important  for  performance of modules which update the attribute table, for example v.to.db,
       v.distance and v.what.rast.

Privileges

       Because MySQL does not support groups of users and because only MySQL  'root'  can  grant  privileges  to
       other users GRASS cannot automatically grant select privileges on created tables to group of users.

       If  you  want  to  give privilege to read data from your mapset to other users you have to ask your MySQL
       server administrator to grant select privilege to them on the MySQL database used for  that  mapset.  For
       example, to allow  everybody to read data in from your database 'mydb':

       shell> mysql --user=root mysql
       mysql> GRANT SELECT ON mydb.* TO ''@'%';

Schemas

       Because  MySQL does not support database schemas the parameter ’schema' of module db.connect should never
       be set to any value. If you set that parameter for MySQL driver GRASS will try to  write  tables  to  the
       specified schema which will result in errors.

Groups

       MySQL  does not support user groups. Any settings specified by 'group' parameter of module db.connect are
       ignored by GRASS for MySQL driver.

SEE ALSO

        db.connect, SQL support in GRASS GIS

Credits

       Development of the driver was sponsored by Faunalia (Italy) as part of a project for ATAC.

AUTHOR

       Radim Blazek

       Last changed: $Date: 2012-09-07 01:20:29 -0700 (Fri, 07 Sep 2012) $
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